guns. In order that the mass of metal may be of uniform
tenacity and character, it should cool equably. This has been secured by
a plan for introducing a stream of water through the core of the
casting, so that the metal cools both within and without simultaneously.

About the time that the Italian war commenced, the subject of rifled
cannon excited much popular interest. Exaggerated expectations were
formed of the changes to be produced by them in the art of warfare. Many
saw in them the means of abolishing war entirely. Of what use is it,
they said, to array armies against each other, if they can be destroyed
at two or three miles' distance? At the commencement of our own contest
there was an undue partiality for rifled ordnance. Almost every
commander of a battery desired to have rifled guns. The more correct
views of the thoroughly accomplished artillery officers to whom was
confided the arrangement of this branch of the service, and actual
experience, have dissipated the unfounded estimate of their utility for
field service, and established the proper proportions in an artillery
force which they should compose. It has been ascertained that fighting
will never be confined to long ranges--that guns which can throw large
volumes of spherical case and canister into lines only a few hundred
yards distant are as necessary as ever.

The necessity for rifled cannon arose from the perfection of rifled
muskets. When these arms reached such a degree of excellence that horses
and gunners could be shot down at a distance of one thousand yards, the
old-fashioned smooth-bore artillery was deprived of its prestige. To
retrieve this disadvantage and restore the superiority of artillery over
musketry in length of range, methods of rifling cannon for field service
became an important study. For assailing distant lines of troops, for
opening a battle, for dispersing bodies of cavalry, for shelling
intrenchments, for firing over troops from hills in their rear, rifled
guns are of invaluable service. But, notwithstanding troops are now
universally armed with muskets of long range, no battle of importance is
fought without close engagements of the lines. The alternate advances
and retreats of the infantry, firing at distances of less than one
hundred yards, charging with fixed bayonets and frantic shouts, will
always characterize any battle fought with vigor and enthusiasm. In such
conflicts, wide-mouthed smooth bores, belching their to